Strange holes in clouds: It's not UFOs, folks

A new study in the journal Science suggests that airplanes can induce small amounts of rain and snowfall by punching "holes" in cloud cover. So what exactly do these holes look like, and how are UFOs involved?

A hole forms above the Danube River

This cavity in the clouds formed in August 2008 just south of Linz, Austria. In its center hovered a battleship-gray mist that did not have any extraterrestrial intelligence and also was not an army of microscopic robot ships prepping to overturn earthly society.